Multimode fiber is designed to operate at 850 and 1300 nm, while singlemode fiber is optimized for 1310 and 1550 nm. Among the most commonly used fiber types are single-mode fiber (SMF) and multimode fiber (MMF), often paired with 1310nm SFP modules for high-speed data transmission. In this guide, we will explore the distinctions between 1300nm and 1310nm transceivers, examine the characteristics of SMF and MMF. In optical transceivers, wavelength refers to the nominal center wavelength of the transmitter laser.